wells



D. G. WELLS.

Steam Gage.

Patented Aug. 11, 1857.

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UNITED STATES PATENT oEEIoE.

D. G. WELLS, OF NEl/V'YORK, N. Y.

STEAM-GAGE.

Specification of Letters Patent No. 17,988, dated August-11, 1857.

To all whom it may concern Be it known that I, D. G. l/VELLs, of the city, county, and State of New York, have invented a new and useful Improvement in Steam-Gages; and I do hereby declare that the following is a full and exact description of the same in all its essential parts.

The general features of this instrument consist of a case with a circular dial and index all in the usual form. The pressure to be measured or indicated is applied within a flattened elastic tube which is placed within the case and which is folded together so as to present a series of layers of the tube, each layer operating against the succeeding layer in such a manner that the final layer or closed end of the tube will have a motion proportionate to the number of layers used. The motion thus obtained is transmitted through a toothed sector and pinion shaft to an index which moves over a graduated arc on the dial.

In order to explain my improvement more fully reference is had to the annexed drawings.

Figure 1 is a front view with the dial re moved to show the parts more distinctly. Fig. 2, is a sectional side elevation, like letters referring to like parts.

A is the flattened tube with the layers a, b, c, d, 6, bearing one upon the other, and having'their point of contact at or near the center of each layer. The upper end of the tube is closed but there is a continuous passage through all the layers of the tube which communicates wit-h a steam boiler or other vessel, through the socket B and pipe C. The motion of the upper layer 6, is transmitted to the index E, through the segment arm F, and pinion shaft G, which multiplies its range of motion in order to make the indications more distinct on the dial D.

The coil spring I is attached one end to the pinion shaft, and the other end to the stationary frame K, and serves to take up all the lateral play of the moving parts, and also keeps the projection H, of the arm F, pressing down upon the tube.

Fig. 3 is a lateral section of the tube on a line through its center and shows the continuous passages through all the layers of the tube. Fig. 4, is a transverse section of the same on a line through the center of the socket B, and shows the flat sides of the tube to be much thinner than the curved part or edges thereof. The object of this uneven thickness in the transverse section of the tube is to allow the flat part to yield more readily to the pressure while the edges being much thicker are prevented from yielding beyond their limit of elasticity.

WVhen a pressure above that of the atmosphere is applied within the tube all the flat surfaces become curved outwardly which gives an upward movement to the layer 6, and the index is thus carried forward over the graduated are on the dial with a movement proportionate to the de gree of pressure applied.

The divisions of the arc are found by subjecting the instrument to various degrees of pressure in connection with a good mercurial gage. When a pressure below that of the atmosphere is applied within the tube all the flat surfaces become curved inwardly which causes the index to move in the opposite direction and the instrument is then a vacuum gage, or it can be used as a barometer by withdrawing the air from the interior of the tube and then closing it hermetically. The number of layers used will of course depend on the range of motion required for the final layer and can be varied at pleasure, and the tube can be arranged to operate in any other position than that herein represented, as circumstances may require.

I claim The use of a flattened tube when 0011- structed and arranged in layers substantially as herein described and for the purposes set forth.

D. G. WELLS. Witnesses WILLIAM E. FRosT, HOWARD L. Horn 

